Compensator sheave



Ap 3, 1934. H. v. MccoRMrcK COMPENSATOR SHEAVE Filed Oct. 29. 1932 mvENToR Haroid M/WQ br/Wick.

WITNE SES:

Patented Apr. 3, 1934 UNITED STATES PATENT OFFICE COMPENSATOR SHEAVE Harold V. McCormick, Wilmette, Ill., assignor to Westinghouse Electric Elevator Company, Chicago, Ill., a corporation of Illinois Application October 29, 1932, Serial No. 640,179 6 Claims. (Cl. 187 22) My invention relates to idler sheaves and. more The invention itself, however, both as to its particularly it pertains to a compensator sheave organization and its method of operation, tofor tensioning and restraining the compensating gether with additional objects and advantages l cables of elevator systems. thereof, will best be understood from the fol- In modern elevator systems it is customary to lowing description of a specific embodiment, when 6uy provide compensating cables connected between read in conjunction with the accompanying the car and the counterweight for preventing the drawing, in which: unbalancing` of the system, as the hoist cables Figure 1 is a side elevational view of my cornpass over the hoist sheave from the car side to pensator in operative engaging relation with an 'lo the counterweight side, and vice versa. A Weightassociated guide rail; and 65? ed idler sheave is usually suspended in the loop Fig. 2 is a section view thereof taken on line of the compensating cables to restrain and guide II-II. the cables, and to maintain a predetermined ten- Referring' more specically to the drawing, sion thereon. the device comprises a cable receiving sheave 1 @5i Difliculties have been encountered with the which hangs in the loop of the compensating 70 car or the counterweight continuing to rise and cables 2 near the bottom 3 of the elevator hatchdeveloping slack cables, when the descent of Way. The hub of the sheave 1 is provided with the other body is suddenly checked, and therea bearing 4 through which a shaft 6 extends. The after falling back and snapping the cables with ends of the shaft 6 extend into orifices provided possible injury to the equipment and passengers. in guide blocks 8 where they are secured by suit- 75L- Additional trouble has also been caused by the able set screws 9. A passageway l0 may carry weighted compensator sheave dying up from the grease through the shaft to bearing 4.

bottom of the hatchway and then falling back Each guide block 8 is provided with laterally andsnapping the cables, projecting guide shoes l2 which engage vertically Previous attempts to avoid these difficulties by disposed guide rails 13 secured on the bottom 3 801 fastening the compensator sheave down to the of the hatchway in any suitable manner. The bottom of the hatchway have not been successful sheave 1 hangs on the compensating cables 2 and since the total length of the cables in the sysrotates freely 0n the Shaft 6 Which iS held from tem does not remain constant, but varies in rOtatOn by the guide biOCkS 3.

accordance with changing conditions of wear, l The upper end 0f each guide bleek 8 iS provided 85 loading and temperature. Hence, when the with a depressed socket 15 which receives the cables were locked down in such a manner as to lower end of a long heavy Compression spring 16 make a rigid system, abnormal detrimental and a short smaller spring 17 in concentrically stresses were set up, disposed relation. Resting on the upper ends of `I t is accordingly an object of my invention the heavy Springs 16 iS a Weight frame 18 corn- 90l to provide a normally free moving elevator comprising a InaSSiVe Castings Or fabricated Structure, pensating cable sheave which will resist upward having an Open Dertien 19 in each Side Wall to movement in excess of a predetermined rate. reeeiVe the guide blOCkS and Springe. The upper Another object of my invention is to provide edge 0f eaeh Opening 19 iS previded with a socket an elevator compensator sheave which will pre- 21 Wheh Opens dOWnWarllly t0 reeeve the upper 95V vent the formation of slack cables byeither the ends 0f the Springs. The heavy Springs 16 have car or the counterweight continuing to ascend Sueient resilience t0 Support the weight frame after the other body is suddenly retarded and 18 a predetermined distance frOrn the 4guide which permits the cables to move freely under blocks 8, and in normal operation when the normal conditions. sheave 1 is raised or lowered gradually by con- 100 A further object of my invention is to provide traction or expansion of the compensating cables, a normally free moving device for guiding and this relation is not disturbed. Additional weights tensioning the compensating cables of an elevator 22 may be bolted to the weight frame 18 as system which will resist sudden abnormal movedesired. 504 ments. In order to guide the movements of the Weight 105 It is also an object of my invention to provide frame, it is provided on each side with suitable a lock down compensator sheave of simple rugged laterally prejeeting pairs Of guide ShOeS 23 adjadesign which will move smoothly between its Cent its 10We1 and upper edges fOr COOperatiVe guide rails to permit unlimited normal expansion engagement With the Same Vertical guide rails 13 or contraction of the cables. which also serve to guide the movements of the 11 guide blocks 8. One of each of the lower pairs of guide shoes 23 is provided with an inner surface 25 which is inclined at an angle to the guide rail 13 in addition to a vertical surface 26 which is disposed adjacent the guide rail for cooperative engagement therewith. A wedge 31 is provided for slidable engagement between the inclined surface 25 and the guiderail 13 to apply a braking force resisting upward movement when predetermined conditions occur.

The actuation of the wedge 31 is controlled by a lever 32 to one end of which it is pivotally secured. The lever 32 is mounted on the weight frame 18 on a stationary pivot 33. The outer end of the lever 32 is pivotally secured to a link rod 34 which extends through a bracket 35 projecting laterally from the guide block 8. A resilient means such as a compression spring 36 is provided in concentrically disposed relation on the upper portion of the link rod above the bracket. The upper end or the rod, which is threaded, receives a nut 37 and a washer 38 to hold the spring 36 in engaging relation on the rod and the bracket.

In normal operation, variations in the length of the cables are caused by varying temperature conditions, by varying stresses set up by changing load conditions, and by the operation of the system to accelerate or retard the load. During such conditions my compensator tensions the compensating cables at all times without jerking or wearing the guide rails or the cables, since it is free to slide up and down on the rails.

If some abnormal condition occurs which causes the compensator sheave to be jerked up suddenly, the weight frame will lag because of its inertia, the guide blocks 8 will compress the springs 16 and move upward relative to the weight frame 18 thereby pulling up the link rod 3ft and rotating the lever 32 to thrust the wedge 31 between the inclined surface 25 and the guide rail 13. The wedge binds between the rail and the inclined surface of the guide shoe thereby applying a braking force which resists upward movement of the weight frame 18. Any movement of the frame upward will cause the wedge to bind still more rigidly against the guide rail.

The spring 36 on the link rod 34 protects the wedge actuating members from breakage by continued upward movement of the guide blocks after the wedge has become rigidly engaged. The upward movement of the cable sheave and the guide blocks is limited by the compression of the heavy springs 16 and the smaller springs 17 which are also compressed against the weight frame.

Since the sudden upward movement of the cable sheave is limited, the danger is avoided of either the elevator car or the counterweight rising and developing slack cables and then falling back and snapping the cables when the other body is retarded suddenly.

It will be apparent that I have provided an elevator compensator sheave which, under normal operating conditions, is free to gradually rise and fall any distance necessitated by the stretchncsa-11e ing of the cables while applying a constant ten-l sioning force thereto, and which does not wear the guide rails and compensating cables by continual gripping and jerking, and which is of simple, rugged construction.

Although I have shown and described a certain specific embodiment of my invention, I am fully aware that many modiiications thereof are possible. My invention, therefore, is not to be restricted except as necessitated by the prior art and the scope of the appended claims.

I claim as my invention:

1. A device for tensioning and guiding elevator compensating cables comprising a cable receiving sheave, inertia means, mounting means including resilient member for supporting said inertia means on said sheave, guides for restraining the movements of said sheave and said inertia means, a brake for engaging said guides t0 retard said inertia means, and means responsive tc a predetermined relative movement between said inertia means and said sheave for applying said brake.

2. A device for tensioning and guiding elevator compensating sheaves comprising a cable receiving sheave, inertia means, mounting means for supporting said inertia means resiliently on said sheave, guides for restraining the movements of said sheave and said inertia means, an inclined plane carried by said inertia means adjacent each guide, wedges, and means responsive to a predetermined relative movement between said inertia means and said sheave for moving said wedges between said guides and inclined planes.

3. A compensator for elevators comprising a cable receiving sheave, an inertia device, resilient means connecting the sheave and the inertia device, a brake for controlling the movements of the sheave and means responsive to a predetemined relative movement of the sheave and the inertia device for operating the brake.

4. A compensator for elevators comprising a cable receiving sheave, an inertia device, resilient means connecting the sheave and the inertia device, a brake for controlling the movements oi the sheave, and means responsive to a predetermined relative movement of the sheave and the inertia device for operating the brake, said brake operating means including a resilient element for protecting the brake from breakage by a continuation of said relative movement.

5. A compensator for elevators comprising a cable receiving sheave, an inertia device, means for supporting the inertia device on said sheave, 13G 

